Establishing An Apl Shared Variable - IBM 5110 User Manual

ESTABLISHING AN APL SHARED VARIABLE
A variable must be offered to the I/O processor before the variable
can become a shared variable. To do this, you must use the OSVO
(shared variable offer) system function. The OSVO function requires
two arguments; the left argument must be 1 (to specify the 5110 I/O
processor), and the right argument must be character data that
represents the variable name{s) to be shared. If more than one name
is required, the names may be entered as a character matrix with each
row representing an individual name. For example:
:I. [] S V () 'A' .....
, - - - - - - T h e variable name A is
offered to be shared.
1.
OSVD 3 lp'ABC'
The vLable names A, B, and Care
offered to be shared.
The OSVO function generates an explicit result of 2 for each variable
name that is successfully established as a shared variable with the I/O
processor. For example:
X~l
OSVO 3 lp'ABC'
X
2
~.~
I')
.:..
~
There are two users of the shared variable, the
active workspace and the I/O processor. This is called
the degree of coupling.
A 0 or 1 is the result of the OSVO function for each variable name that
is not successfully shared with the I/O processor. If the result is 1,
the left argument of the :DSVO function was a value other than 1. In
this case, the variable name must be retracted and offered as a shared
variable again with a 1 as the left argument of the OSVO function
(retracting the shared variable name is discussed later in this chapter).
If the result is 0, an error message is also displayed.
You can establish up to 12 shared variables in the 5110 active
workspace. If you attem'pt to establish more than 12 variable names
as shared variables, the error message INTERFACE QUOTA
EXHAUSTED is displayed. The statement
(0 t-I]SVD []NL.. 2) f[]NL.. 2
displays the existing shared variable names in the active workspace. If
12 shared variable names are already established, you must retract a
shared variable name before another variable name can be offered.
Input/Output Control 117